I am interested in the irrational. I have the usual layman's understanding of the double-slit experiment, which I am told is the cornerstone of quantum irrationality. I have a question to clear up my understanding of this, and a few more questions about irrationality in physics. You will soon see that I am not a scientist or expert. My grasp of scientific nomenclature is weak at best, and I have quite a naive understanding of modern scientific discoveries. Please, if you reply, can you assume you are talking to a bright GCSE teenager rather than a professor of differential calculus. 1. The double slit experiment works with matter or light, right? What are the "particles" ("quanta"?) that are fired at the slits? 2. The particles "know" when they are being measured, right? They are behaving like waves, going through both slits, and then when they are measured they suddenly only go through on slit, right? 3. What the double-slit experiment must "mean" is that the elementary particles of light / matter are behaving in a way that the brain cannot adequately imagine, in the same kind of way that the brain cannot imagine a line infinitely long, or an object that must be spun 720 degrees to get back to its original point. 4. I seem to remember reading of a particle like this, that has to be spun twice to get back to the start. Is this right? 5. What other unimaginable or irrational things happen in the quantum world? Can someone give me, or point me towards a nice little list of things that happen that don't make sense, or rather that can't make sense because they are paradoxical or somehow infinite? 6. Like I say, I am very interested in the relationship between infinity, paradox and the unimaginable. Anything that anyone has to say that might open up new explorations of these themes would be welcome. I'm not interested in "psuedoscience" or religion (at least abrahamic religion), rather aesthetics and the nature of perception. 7. Finally, on a completely different topic, probably not physics at all, I recently read that "systems theorists have shown that natural systems and organisms have an innate tendency to move towards complexity, creating a structures which are more than the sum of parts. Apparent order and complexity are not created by genetic mutations, but by the innate emergent properties of matter." Is this so? Where can I read more about this? Thank you for your time.